Dispersants containing terminal acidic groups, such as, carboxylic acid (such as derivatives of 1,2,4-benzenetricarboxylic acid), phosphates and sulphates are known. The phosphate and sulphates are generally, prepared by reaction of a hydroxy ended polymer chain with phosphorus pentoxide, phosphorus oxychloride, polyphosphoric acid or sulphuric acid. The dispersant polymer chains are often derived from polyester or polyalkoxylate chains containing terminal hydroxyl groups. Dispersants known in the art containing terminal acidic groups are suitable for a polar medium, such as, water, ketones, esters and the like. However, it would be advantageous to utilise the dispersant properties of compounds containing terminal acidic groups in both a polar and a non-polar organic medium. The present invention provides such a dispersant and compositions thereof.
U.S. 2005/0120911 and U.S. 2004/0039946 disclose polymeric dispersants prepared from a Jeffamine monoamine and 1,2,4-benzenetricarboxylic acid anhydride and a polyisobutylene amine and 1,2,4-benzenetricarboxylic acid anhydride, respectively. The former agents are used as dispersants on inorganic and organic lake pigments in polar solvents such as ester and alcohols and are not useful in non-polar solvents such as aliphatic mineral oil. The latter agents are used as dispersants in non-polar solvents only and cannot be used in polar solvents.
U.S. Patent Application Ser. No. 60/750,479 discloses polyether amine based dispersants containing a polar inorganic group. The polar inorganic group includes groups such as a sulphur or phosphorus acidic polar head group.